MacCulloch's 1840 Geological Map of Scotland, facsimile edition (a reproduction of the third issue of the map scanned from the original held in the British Geological Survey archives, reproduced half-scale at eight miles to the inch, size 74 × 93 cm, supplied flat only), 2007, British Geological Survey, Edinburgh. ISBN 9780751835007. £10 plus postage (available from BGS, Edinburgh; email: scotsales@bgs.ac.uk).

In the preface to the 1836 Memoir of MacCulloch's geological survey of Scotland, which accompanied the map, Samuel Arrowsmith penned the following lines: 'The following "Memoirs" have been printed verbatim from the manuscripts of the late Mr. MacCulloch, without note or comment. His sudden and lamented death has prevented my remarking on certain of his opinions and statements; but these, it is hoped, will be received as he meant them to be, by such as are competent judges of the real errors and deficiencies in the unfortunate Map, that became so fertile a source of his indignation'.

These rather negative lines hide a 20-year story of one man's involvement in pursuing a line of arduous investigation that culminated in a masterpiece of mapping that ranks amongst one of the greatest achievements in geology during the early to mid-nineteenth century. John MacCulloch's geological map of Scotland stands alongside William Smith's 1815 map of England and Wales and Richard Griffith's 1838 map of Ireland as the foundation stones upon which all later work has been laid. James Nicol's 1844 geological map of Scotland drew upon MacCulloch's map as a base for his own investigations, with Nicol stating his indebtedness to MacCulloch (1773-1835) and others who pioneered such work.

Others, however, were less than charitable, particularly Murchison who stated that the map 'was so replete with errata that it would be a waste of time to attempt to enumerate them'. However, Murchison's opinion should be treated with caution as he was highly critical of MacCulloch's views, which culminated in a stinging attack when Lyell's Principles of Geology were first published. This unfortunately coincided with the eventual publication in 1831 of MacCulloch's two-volume student text on the System of Geology which had been written a decade earlier (MacCulloch 1831). Murchison wrote 'If you wish …